Pneumatic tool



May4 19,' 1925.

A. LEVEDAHL PNEUMATIC TOOL 5 Sheets-Sheet l Filed July 50, 1.919

A. LEVEDAHL May 19, 1925.

PNEUMATIC TooL Filed July 3o, 1919 5 sheets-Sheet .2

May 19, 1925.

A. LEVEDAHL- NEUMATIc TooL Filed July 130.A 1919 llllllllllllll IIIIIIIIIIII MTW.

Patented May 19, 1925.

UNITED STATES PATENT OFFICE.

AXEL LEVEDAHL, OF AURORA, ILLINOIS, ASSIGNOR TO INDEPENDENT PNEUMATIC TOOL COMPANY, 0F CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

PNEUMATIC TOOL.

Application led July 30, 1919. Serial No. 314,374.

To all whom z5 may con-ccm Be it known that I, AXEL LEvEDAHL, a citizen of the UnitedV States, residing at Aurora, in the county of Kane and State of Illinois, have invented new and useful Improvements in Pneumatic Tools, of which the following is a specification.

This invention relates to improvements in pneumatic tools and more particularly to sand rammers of the floor type, and consists in the matters hereinafter described and claimed.

In the drawings Fig. 1 is a side elevational view of a pneumatic sand rammer embodying the features of my invention;

Figs. 2 and 3 are, when considered collectively, a longitudinal sectional view through the sand rammer, on a scale somewhat greater than that shown in Fig. l;

Fig. 4 is a longitudinal sectional View through the throttle stem of the rammer.

Fig. 5 is a side elevational view of the combined piston and plunger with one end thereof broken away to illustrate a detail of construction;

Fig. 6 is a transverse sectional view taken on line 6 6 of Fig. 4;

Fig. 7 is a perspective view of the throttle valve stem;

Figs. 8 and 9 are transverse sectional views taken on lines 8- 8 and 9 9 respectively, of Fig. 2;

Fig. 10 is a side elevational view -of the locking pin and its spring;

Fig. 11 is a longitudinal sectional view taken on line 11-11 of Fig. 1;

Fig. 12 i-s a transverse sectional view taken on line 12-12 of Fig. 11; and

Fig. 13 shows the manner in which the cap of the valve block is applied thereto.

A sand rainmer embodying the features of my invention comprises a barrel 1 on one end of which is threaded a valve housing or head 2. Said barrel has the usual bore 3 for a reciprocating piston 4, provided with a rod 5 which extends beyond the opposite end of said barrel and has removably connected therewith a stamper or pien 6. Said barrel is provided with the usual passages 7 for the operating Huid, the admission and exhaust of which to and from the barrel, on opposite sides of the piston, being controlled by a valve 10 in the block 8 in the housing or head 2 as in pneumatic tool design. A cap or disc 9 closes the adjacent ends of the block 8 and the barrel 1. The valve block 8 and the disc 9 are held in alignment with the barrel at one end, and a shoulder 11 in the head 2, prevents endwise displacement of the parts in that direction. The said valve block 8 has a tubular extension 8a, provided' at its outer end with an annular, undercut groove 8b into which is forced a concave cap 8", as shown in Fig. 13. Said cap 8 is flattened out to lit snug and air tight in said groove and closes the end of the extension. The piston valve 10 has a cylindrical extension 1()a which fits air tight in the tubular extension 8a and is fed with live air through radial ports 8d which communicate at all times with the live air supply. Thus there is a live air pressure constantly on the valve extension 10a. This tends to continuously force the valve forward, but as said valve is reversed by reason of the pressure on its larger pressure area, the live air in the valve block extension St1 is forced back into the supply, and thus no live air is lost in this operation, eX- cept what might leak through, in case the valve becomes worn. In connection with the ports 8d, I provide in the valve block other radial ports 8e which open into the valve bore in the block. These ports take care of leakage at this pointand also relieve the vacuum formed at this point when the valve 10 moves forwardly.

The piston 4 is made hollow, for the purpose of lightness, and in its open top end is provided an annular, undercut recess 12 into which is forced a concave cap or disc '13, which when flattened out, is locked against displacement.l Figure 5 shows the cap 13 before it is forced into the recess 12, and Figure 2 shows said cap after it has been forced into and flattened out in said There is a second -turiiing of the nut. y y varecess 27 torine'd in the end 'ofthe-barrel struction.

ring 18 having an outwardly projecting, radial 'lug :19 (see fFig. 0) :extending into a longitudinal groove 20 in the-'barrel l1. Between said rings are interposedcompressible gaskets 21, .21, preferably inade of leather.

The rings and `gaskets are provided with parts which extend into the flutes 15, 15, as shown in Fig. 9. A nutihaving': a screw body 22 threaded into the forward end of the barrel, actstoiiorce theliing 18 towards the ring 16 and compress the gasketsbetween theni. The head 23-'of-tlie-iiut `is beyondthe end ofthe-barrel randhas a hole 24 (Fig. 1) kin its periphery to vreceive a Spanner wrench or other devicetotigliten kor loosen the'nut. To-lock'the nutfin any of its adjusted positions, I provide in the ace'o'f-the nuttowards `the end o'ffthe'barrel, aplurality of eiicuniferentially spaced, counter-sunk depressions 25, L 25, as shown iii-Figsf2 and S, and whichv co-operatewith la locking pin 26 "projecting beyond the :end

of the'barielfand havinga conical shaped outerendito enter any-one of said depressions 25 and Eto Vratchet therewith, in .the Saidpin 26s1id'es in 1. The '-innerend ofesaid -pin is 'reduced to receive a coi-led expansion spring 2&1, which v'forces Vthe'pin-outwardly. The`last vrtwo loops `at 'the innerf-endfthe spring are made olfia diameter-slightly greaterI than that of the recess 27, to hold the spring ftherein, andas the loops at'A the opposite'end of the vspring 4tightly engage/about the "ad jacent'endo'flthe pin 26, the latter andfthe spring are .prevented froin :dropping or beouterV end of the pin'26, is a :groove "29 .to permit a sciew driver'or otheriinplenient vto be 'engaged with the pinto loosen-the sanie should'it biiid in said'reeess 27. After the nut"y has been tightened, the pin will .en-gage in the saine `and hold the nut 'from `accidental rotation.

vl`o'51ock-the head oi"valveiho.using 2 to the'ba'riel il, Vprovide the following'con- Said-'barrel 1 is provided adjaccntgits uppei'end with'a'n annular rib k31 against which bears alocking ringlQ, surrounding the barrel. HIiitei'posed between said ring` 'B2 'and the opposed vend yof ithe vhousing r2 is -a coiled-expansionspringr 33 surrounding the'harrel and having its ends bent in opposite directions 'to enter'pock- 'ets or recessesa, BSb'in thering andhead respectively, as shown in yFig. 1. 1n that tace-of the ring "32 opposedtoftheribSl is-a plurality of ratchet teeth'34 (Fig. 12),

between two ot which 'the -teoth 35 :'(Fig.

1l) of a locking-key 36 engages. Said -key 36 isin thef'orin ota plughaviiig its base circular vto seatin acorrespondingly shaped socket in the'barrelllatithe rib 31, as shown in Figs. 11 and j12. `-Said key has aslotted the-ring 32. -32-isiprovided a.pluralitvof'holes 32u for :1a 4Spanner -wrench or thelike, torotate said the spring head by n'ieans of which it inay be rotated hyra screw 'driver to release'its tooth 35 troni lockingengageinentw-ith the teeth of In the periphery of said ring ring to increase oi' decrease the tension of As is apparent, this construction prevents any rotation between the barrel-'andE head yuntil it is desired to remove one frein the other for the purpose of inspection or repair. n

The throttle stein or casing Vv36 for l the rainnier, is tubular and is connectedby Aa 'tube 'with the valve housing 2in 'any preferred 'inannen The upperend of said stein *36 is threaded to'perinit an air supply hose to be connected therewith. Said throttle sten'i`l3`6`is providedbetweenits lends with A'a bore arranged at an vinclination tothe longitudinal 'axis of said stein Yand-in which isloea'tefd atubular'hushing 8S. 'Said bu'shing' 38 is provided with a valve seat B Q'ifor a ball'. valve 40, which -is normally `held against said seatf-by'a spring t1 interposed -betweenthe saine and aserew 111042 closing` one end of said bushing. The opposite end of saidbushingBS is reduced'and reuceives a valve stein 43 resting -at one end 'on said ballvalve and projecting atits other beyond said bushing, ias shown in lfFigs. 3

and i. Said stein 13 is L*provided with an annular groove .L14 which ynormally regis- 'tei-s" with ports Il5' and 16; inl the bushing 'and throttle stem respectively. Said valve stein Fis provided with a "groove 41-7 connecting the Vgrooveli with the spacefa'r'ound the reducedlziart 48er said stein,"so that when the ball valve is closed, any?leakagel of air: to the vatmosphere "is 'through *the 'groove 47 'and .ports 45 and 4G, thus guarding against Iaccidental' operation off the'raii'inier, due` toleakagebetween the hall valve and' its seat. The bushing 38 is provided with two xports 49 `and y50 on opposite endsv of'zth'e valve seat 39 and in substantialaligninentlwith the longitudinal axis of thepassagewaythrough the throttle'stem/361W a stud orpin'52. Said lever '51 is provided between i its YVends with 'an "offset portion or V hood '53, arranged at right anglestolthe'valve stein andinade to enclose and conta-et against the upper-or outerendof the saine. Pivotally-secured )to thethiottlestein- 36 at the-free end of the fleverf51, is abail-Bi, adapted tobe swung over the `ifree end of said `lever toholdthe samein contact --Withfthe throttle stein and the ball valve 40 open. When the lever 51 is released from the bail 54, the spring 41 acts to close the ball valve against its seat and to return the lever into its normal posi tion, as shown in Fig. 3, where the rear end 5la of said lever engages against the throttle stem and limits the outward movement thereof.

Located in the valve housing 2 in advance of the valve block 8, there is a strainer or screen to prevent scale and the like from entering the ports and passages in the valve block 8, the screen being held in place by an expansive split ring 56.

By connecting the throttle stein 36 with the barrel l, the tool as a whole has such a length that it permits the operator to handle the tool while standing in an erect position and yet allow the stamper 6 at the lower end of the tool, to reach the mold on the floor. The operator grasps the tool about its throttle stem 36 above the throttle valve 40, and draws the free end of the lever 51 against and into contact with the throttle stem, thereby opening the ball valve 40. The lever 5l may be held in suoli position, independent of the operators hand, by the bail 54. The lever 5l has a transverse curvature correspending to the contour of the throttle stem 36 so as to fit against the same and permit the hand of the operator to grasp it while holding the tool in an easy and natural manner.

The construction above described, possesses many advantages. A straight live air passage is provided through the throttle stem and with the throttle valve stem set at an inclination thereto, the width or thick-- ness of the stem is materially reduced at this point, thereby producing a neat and compact arrangement of parts and giving the tool a substantially uniform diameter throughout its entire length convenient for grasping. Furthermore, the ports 49 and 50, in said bushing, are substantially in line with the said passageway in the throttle stem, so that when the ball valve is moved away from its seat, the live air travels in a straight path. The hood 53 of the lever l shields the valve stem and acts to prevent the entrance of sand or grit at this point and protects the same from abrasive action.

Vhile in describing my invention, I have referred to certain details of construction and arrangement of parts, as included in a sand rammer, I do not wish to be limited thereto, as the invention may readily be embodied in other types of pneumatic tools where its peculiar characteristics make it advantageous to do so.

I claim as my invention:

l. A throttle valve, comprising a substantially straight tubular casing having a substantially straight live air passage extending longitudinally therethrough, a bushing in said casing intermediate the ends thereof and extending across said passage at an inclination thereto, said bushing having ports opening into said passage on opposite sides of said bushing and being aligned with each other and with the longitudinal axis of said passage, a valve seat in said bushing between said ports, a self closing valve in said bushing, and a pivoted lever on the outside of said casing and engaging said valve for opening the same upon moving said lever toward said casing.

2. A throttle valve, comprising a tubular casing having a live air passage extending therethrough, as self closing valve mounted in said casing intermediate the ends thereof and having a stem projecting outside ofv said casing, a seat in said passage for said valve, a lever pivoted to said casing on the outside thereof at one side of said valve and extending over and engaging said stem for opening said valve upon moving said lever toward s aid casing, said lever having a transverse curvature corresponding to the contour of said casing for allowing the lever to be in contact therewith when holding the valve open, and a bail pivoted on said casing adjacent the free end of said lever for engaging the same and holding the lever against the casing.

In testimony that I claim the foregoing as my invention, I ailix my signature this 26 day of July, A. D. 1919.

AXEL LEVEDAHL. 

